<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>字符串连接“+”</title>
</head>
<body>
<script type="text/javascript">
 var x=10,y='4';
 document.write("x="+x+",y="+y+"<br/>");
 document.write("(x+y),结果"+(x+y)+"<br/>");
</script>
</body>
</html>